1. Field of the Invention
The present invention relates to a wireless communication apparatus which can simultaneously conduct communication through plural frequency channels and a communication party on the other end which switches among frequency channels.
2. Description of the Related Art
Conventionally, in the case where a wireless communication terminal being connected to a wireless communication base station, changes a frequency channel while the wireless communication terminal scans to see whether or not there is a wireless communication base station connectable on the new frequency channel, and confirms whether or not the wireless communication base station whose existence is confirmed by the scanning is a proper wireless communication base station, whereby the wireless communication terminal sends a connection request to the wireless communication base station. When the wireless communication base station permits the wireless communication terminal to be connected thereto in response to the connection request, the connection is completed, and the wireless communication terminal starts the communication with the wireless communication base station.
There are a procedure for moving a wireless communication base station and wireless communication terminals connected thereto to another frequency channel and a procedure for moving an entire system consisting of only wireless communication terminals to another frequency channel (for example, see IEEE Std.802.11—2007, “IEEE Standard for Information technology—Telecommunications and information exchange between systems-Local and metropolitan area networks—Specific requirements; Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications”, IEEE Computer Society, Jun. 12, 2007). In addition, there are some studies for a system in which communication is simultaneously conducted on plural frequency channels (for example, see R. Lyenger, et al., “Analysis of Contention-based Multi-channel Wireless: MAC for Point-to-multipoint Networks,” Proc. of the 2006 International Symposium on a World of Wireless, Mobile and Multimedia Networks (WoWMoM '06), 26-29 Jun. 2006, 3 pp., Y Huang, et al., “Architecture and Scheduling Algorithm for a Multi-Channel Wireless Infrastructure Network with Diversity Management Layer,” Proc. of The 44th IEEE Conf. on Decision and Control, and the European Control Conf. 2005, Dec. 12-15, 2005, pp. 406-410, R. C. Daniels, et al., “Multi-band Modulation, Coding, and Medium Access Control,” doc.: IEEE 802.11-07/2780r1, November 2007, JP-A Nos. 2006-246115 (KOKAI), 11-205352 (KOKAI), 2004-32210 (KOKAI), and 2002-77965 (KOKAI)).
In IEEE 802.11 wireless LAN, from the viewpoints of coverage securement and effective utilization of frequency channels, there is a discussion that plural frequency channels are shared under one wireless communication base station (for example, see R. C. Daniels, et al., “Multi-band Modulation, Coding, and Medium Access Control,” doc.: IEEE 802.11-07/2780r1, November 2007). There are a system in which a control station collects pieces of information on wireless communication base stations to allocate an optimum communication channel to wireless communication terminals (for example, see JP-A No. 2006-246115 (KOKAI) and Y. Huang, et al., “Architecture and Scheduling Algorithm for a Multi-Channel Wireless Infrastructure Network with Diversity Management Layer,” Proc. of the 44th IEEE Conf. on Decision and Control, and the European Control Conf. 2005, Dec. 12-15, 2005, pp. 406-410), a system for allocating a communication protocol to wireless communication terminals (for example, see JP-A No. 11-205352 (KOKAI)), a system in which a wireless communication base station that can conduct communication on plural frequency channels newly allocates a frequency channel to a terminal requesting communication according to wireless condition (for example, see JP-A No. 2004-32210 (KOKAI)), and a system to hand over a connected wireless communication terminal to another system (for example, see JP-A No. 2002-77965 (KOKAI)).
By the conventional techniques, although a wireless communication base station can perform transmission and reception on plural frequency channels, wireless communication terminals connected to the wireless communication base station cannot recognize that the wireless communication base station can perform the transmission and reception on the plural frequency channels. Accordingly, in the case where the wireless communication terminal changes the frequency channel to another frequency channel on which the wireless communication base station can perform the transmission and reception, it is necessary for the wireless communication terminal to scanning again whether or not there is a connectable wireless communication base station.
Even if plural communication systems such as modulation and coding schemes and security systems can be used by the wireless communication base station, in each frequency, the wireless communication base station does not notify the wireless communication terminals of the communication systems that are supported in other frequencies. Accordingly, in the case where the wireless communication terminal moves to another frequency channel on which the wireless communication base station can perform transmission and reception, it is necessary for the wireless communication terminal obtain information on the communication system with which the wireless communication base station is supported at the frequency channel from the wireless communication base station again.
Thus, it is preferable to be able to make a notification that the transmission and reception can be performed on plural frequency channels. When plural communication systems such as modulation and coding schemes and security systems can be used, it is preferable in each frequency to be able to make a notification of the communication systems that are supported in other frequencies. It is preferable that a wireless communication apparatus can manage the communication systems with which another wireless communication apparatus is supported over plural frequency channels.